The present invention is directed to a load control structure and the control method for a work vehicle.
Such a work vehicle conventionally has, among other things, set rotation speed detection means for detecting a set rotation of an engine of the work vehicle; actual rotation speed detection means that senses an actual rotational speed of the engine; continuously variable speed change device that receives power from an engine of the work vehicle; speed change position detecting means for detecting a speed change operation position of the continuously variable speed change device; operating means for speed-shifting the continuously variable speed change device; control means for controlling the operation of the operating means.
In the load control mechanism mentioned above, the control means controls the control means for controlling the continuously variable speed change device based on the drop amount of the engine rotation speed from a set rotation speed so as to operate the continuously variable speed change device to a speed position in accordance with the drop amount. (See, for example, JP2002-22006.)
In the above structure, the continuously variable speed change device is merely operated to a speed position in accordance with the drop amount from a set engine rotation speed. Thus, it was difficult to have a satisfactory load control that is good for different engine loads that differ depending on operating conditions.